Selective control system for power driven machine tools



Patented Oct. 21, 1 941 SELECTIVE CONTROL SYSTEM FOR POWER DRIVEN MACHINE TOOLS m E. Lillquiat, Milwaukee, we, assignor to Cutler-Hammer, Inc., Milwaukee, Win, a corporation of Delaware Application December 18, 1936, Serial No. 116,657

9 Claims. (Cl. 192-142) This invention relates to selective control systerns for power driven machine tools.

While not limited thereto the invention is especially applicable to controllers for power driven forming presses having a plurality of reciprocable slides each of which is driven through the medium of a clutch and is provided with a brake to be applied upon release of the clutch.

The invention has among its objects to provide an improved push button control system for forming presses of the aforesaid character.

Another object is to provide a controller for power presses of the aforesaid character including cooperatively related automatic and manual control instrumentalities for controlling the clutches and brakes to effect operation of the slides in various ways, as for example inching of the slides selectively, cycling of the slides individually or cycling of the slides in a definite sequence.

Another object .is to provide a controller of the aforesaid character including a master switch which'is readily adjustable to efiect selection of the slide operations.

Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates an erabodiment of the invention which'wili now be described, it being understood that the embodi ment illustrated is susceptible of modification 'are continuously driven in one direction by a motor M through the medium of belts l3.

Referring now to Fig.2, the same illustrates a controller for the forming press/shown in Fig. 1 which includes a normally open electromagnetic switch I! for controlling an energizing circuit for brake I and clutch I and a normally open electromagnetic switch I for controlling an energizing circuit for brake 8 and clutch ii. The control means for switches I5 and i5 includesa master switch II, a plurality of limit switches It to 23, inclusive, associated with shaft 3, a plurality of limit switches 24 to 21, inclusive, associated with shaft 5, and a limit switch 28 which is associated with the slides l and 2. The control means for switches i5 and It also includes normally open electromagnetic relays 29 and 30, a normally open start push button 3i,

' a normally closed stop push button 32, a run push without departing from the spirit and seem of the appended claims.

In'the drawing,

Figure 1 is a schematic view of a multiple slide forming press embodying certain. features of the invention;

Fig. 2 is a diagraatic view of a control sys tem for the press shown in Fig.1, and

Fig. 3 is a detail side elevaticnai view at a conventional type of limit switch which may be used in the control system shown in Fig. 2.

Referring to Fig. i, the same illustrates a forming press including reciprocable outer and inner slides l and 2, the former being operatively connected to a shaft 3 through the medium of a crank 4 and the latter being operativelycconnected to a shaft 5 through the medium of a crank 6. Shafts 3 and 5 are provided with normally engaged electromagnetic brakes I and 8, respectively, and shaft 3 has a normally released electromagnetic clutch 9 associated therewith for connecting the same to a drive, shaft l0, while shaft 5 has a normally released electromagnetic clutch l I associated therewith for connecting the same to a drive'shaft II. The shafts ill and i2 button 33 having normally'open contacts 33 and normally closed contacts 33 and a normally open inch push button 34.

Master switch I! is provided with stationary contacts at to El, inclusive, and a movable contact drum having an ofi position and five difierent operative-positions namely so called long outer inner, long outer, long inner, "inch outer and inch inner positions. Said drum is provided with sets of contact segments for bridging certain of the stationary contacts in each of the aforementioned operative positions, said sets oi contact'segments being designated by reference characters a, b, c, d, and e.

The limit switches it to 23, inclusive, are contrailed in accordance with the angular position oi shaft 3 and the limit switches to 2?, inelusive, are controlled in accordance with the angular position of shaft 5. Each of said limit switches may be biased to move into open position and be provided with a cam operating mechanism of the character shown in Fig. 3 for moving the same into closed position. The limit switch shown in Fig. 3 is provided with an operating arm to be engaged by a pair of overlapping cam elements 53 and 54, each of which is secured to the switch operating shaft by a set screw 55. As is apparent, the cam elements 53 and 54 may be adjusted with respect to the operating shaft to cause closure of the limit switch at any desired angular position of said shaft. Also it is apparent that the cam elements 53 and 54 may be adjusted with respect to each other to vary the period during which the operating shaft acts during each revolution to maintain the switch in closed position.

Limit switch 28 is normally closed and as shown in Fig. 1 the same is mounted upon the outer slide l and is operatively connected to the inner slide 2 to provide for opening thereof it said. inner slide assumes a position too far in advance of the outer slide The function and operation of the aforedescribed controller and also the circuit connections therefor will now be more fully described.

Upon depression of start push button 3|, relay 33 is energized by a circuit extending from line L through said start button and stop button 32,

and through the operating winding 30- of said oi. its working stroke under the action of said brake.

relay to line L. Relay 30 then responds and upon release of start button 3| said relay is maintained energized by a circuit extending from line L by conductor 51 through contacts 30 of said relay through limit switch 28 and stop button 32, and through the operating winding 3|! to line L.

With slides l and 2 in up position the several limit switches associated with shafts 3 and 5 are positioned as-shown in Fig. 2. Assuming that relay 30 is in closed position and that the limit switches are positioned as shown in Fig. 2, movement of master" switch into its long outer inner" position establishes an energizing circuit for relay 29 extending from line L by conductor 51 through contacts 30 of relay 30 to contact 31, through drum segments 31 and 39, to contact 39, through contacts 33'- of run push button 33 to contact 4|, through drum segments 4| 5 and 42 to contact 42, through limit switch 24 and the operating winding 29* of relay 29 and by conductor 58 through contacts 30 of relay 30 to line L. Relay 29 thus responds and in responding the contacts 29 thereof shunt the contacts 33 of run push button 33 to thereby maintain the aioredescribed energizing circuit for winding 29 upon depression of said run push button.

Assuming now that run push button 33 is depressed, circuit is established from line L through contacts 30 of relay 30 to contact 31, through drum segments 31 and 39 to contact 39, through contacts 33 of the run push button, through contacts 29 of relay 29 to contact 40, through drum segments 40 and 44' to contact 44 by conductor 59 to and through limit switch 20 by conductor 60 to contact 41, through drum segments 41 and 48 to contact 48 through the operating winding |5 of switch l5 and by conductor 58 through contacts 30 of relay. 30 to line L Switch I5 is thus energized and in responding the contacts |5 and 15 thereof connect the operating windings of brake 1 and clutch 9 across lines L L Brake l is thus released and clutch 9 engaged to provide for downward operation of the outer slide I.

After a given downward movement of outer slide limit switch 2| closes and upon release of run push button 33 switch I5 is maintained energized by a circuit extending from line L through contacts 30 of relay 30 to contact 31 through drum segments 31 and 46 to contact 46 through auxiliary contacts ii of switch l5, through limit switches 2| and 20 by conductor 60 to contact 41 through drum segments 41 and 48 to contact 48, through the operating winding l5 and by conductor 58 through contacts 30 of relay 30 to line L. Just prior to completion of the working stroke 01' outer slide limit switch 20 is opened to interrupt the energizing circuit for switch l5. Switch l5 then opens to automatically deenergize brake 1 and clutch 9 and the outer slide is brought to rest at the bottom Before limit switch 20 opens to stop the outer through contacts 30 01' relay 30 to contact 31 q through drum segments 31' and 39' to contact 39 by conductor 8| through auxiliary contacts l5 associated with switch l5 through limit switch 22 to contact 50, through drum segments 53 and 5| to contact 5|, through the operating winding it of switch l6 and .by conductor 58 through contacts 30 of relay 38 to line L. Switch I thus responds and in responding the contacts l6 and |8 thereof connect the operating windings of brake 8 and" clutch across lines L 1.. Brake 8 is thus released and clutch engaged to provide for downward operation of the inner slide 2. Upon droppingout or switch II the aforedescribed energizing circuit for switch I3 is interrupted. However, prior to stopping of the outer slide at the bottom of its working stroke limit switch 23 closes and upon dropping out of switch |5 switch I6 is maintained energized by a circuit extending from line L to conductor 3| as already traced, through limit switch 23 and auxiliary contacts lt of switch l5 through limit switch 2I to contact 50 through drum segments 50 and SI to contact 5| and through the opcrating Winding I6} of Switch I to line I? Bl already. traced.

the inner slide is brought to rest in its up position under the action of said brake.. During final movement of slide 2 into its up position limit switch 23 is opened and limit switch 21 is re closed.

Prior to completion of the working stroke of outer slide limit switch I9 is moved into closed position and during return movement of the inner slide 2 toward its up position limit switch 25 is momentarily closed to reestablish an energizing circuit for switch l5 extending from line I through contacts 30 of relay 30 to contact 31 through drum segments 3l and 48" to contact 46 through limit switch 25 by conductor 63 to contact 41 through drum segments 41, 48 to contact 48 through the operating winding l5 and by conductor 58 through contacts 30 of relay 30 to line L. Upon response of switch |5 a maintaining circuit therefor is established from line L through contacts 30 of relay'30 to contact 31 through drum contacts 31' and 45 to contact 45, through auxiliary contacts l5 associated with switch l5 to limit switch 9 by conductor 33 to contact 41 through drum segments 4! and 43 to contact 48 and thence through the operating winding l5 to line L as already traced. Clutch 9 and brake l are thus energized to provide for return of outer slide toward its up position. Prior to full movement of outer slide into its up position limit switch l9 opens to interrupt the aforedescribed maintaining circuit for switch I! and said switch in dropping out deenergizes brake 1 and clutch 9 to provide for stopp ng or said slide in its up position under the action of said brake.

Upon a given upward movement 01' inner slide 2 limit switch 23 is opened and is maintained in open position until final movement of said slide into its up position. Opening of limit switch 23 interrupts the aforedescribed energizing circuit for relay 29 and upon dropping out of said relay the contacts 29 thereof open to render contacts 33 of the run push button ineffective to establish an energizing circuit for switch I5. It is thus apparent that relay 29 is controlled to prevent repetition of the afcredescribed "long inner outer cycle of operation in case run push button 33 is held depressed throughout such cycle.

It should. also be noted in connection with the out of interfering position by means which will bedropping out of said relay Upon-dropping out of relay29 the contacts 29 thereof open to' render push button 3| relay 30 is energized as hereinbefore set forth, and upon response of said relay the operating winding thereof is maintained energized by a circuit extending from line L by conductor 51 through contacts 30 to drum segment 36 to contact 36 and thence through stop button 32 and winding 30 to line L. Relay 2' hereinafter described before either of the slides can be restarted by run' push button 33.

Assume now that both of the slides I and 2 are stopped in their. upper position and that master switch I1 is moved into its long outer position. Upon closure of relay by start push button 3 I, circuit is established from line lll through contacts 30 of said relay to contact 31 through drum segments 31 and 39 to contact 39, through contacts 33 of run push button 33 to contact H through drum segments 3|" and 33 to contact a 33 through limit switch I3 to and through winding 29 of relay 29 and by conductor 58 through contacts 30 of relay 30 to line L. As hereinbefore set forth, upon response of relay 29'the contacts 29 thereof shunt contacts 33 of run push button 33 to maintain winding 29 energized upon depression of said run push button. Assuming now that run push button 33 is depressed circuit is established from line L through contacts 30 of relay 30 to contact 31 through drum segments 31 and 39 to contact 39 through contacts 33 of said run push button, through contacts 29 of relay 29 to contact 30 through drum segments 30 and 38 to contact 38 through the operating winding I5 of switch I5 and by conductor 59 and contacts 30 of relay 30 to line L. Switch I5 thus responds and as hereinbefore set forth the same establishes an energizing circuit for brake 1 and clutch 9 to provide for operation of the outer slide I. As hereinbefore set forth limit switch, I9

closes during downward movement of the outer slide I and upon closure of said limit switch, switch I5 is maintained energized by a circuit extending from line L through contacts 30 of relay 30 to contact 31, through drum segments 31 and 35 to contact 35, through auxiliary contacts I5 associated with switch I5, through limit switch I9, by conductor 60 to contact 31, through drum segments 31 and 38 to contact 36 and thence through the operating winding I5 to line L as already traced. The run push button can thus be released and switch I5 will be maintained energized until the energizing circuit therefor is interrupted by limit switch I9. As hereinbefore set forth limit switch l9 opens just prior to movement of the outer slide I into up position and upon opening of said limit switch the switch I5 is deenergized to deenergize brake] and clutch 9 for stopping of the outer slide I in its up position. Limit switch I8 is opened momentarily during final movement of the outer slide I into up position and upon opening thereof the maintaining circuit for relay 29 is opened to provide for Iii is then energized by a circuit extending from line L through contacts 30 of relay 30 to contact 31 through drum segments 31 and 39 to contact 39 throughcontacts 33 of the run push button to contact through drum segments.3l and 32 to contact 32, through limit switch 23 to and through the operating winding 29' and by conductor 53 and contacts 30 to line L. Relay 29 then responds and maintains itself as hereinbefore set forth. Upon depression of run push button 33 circuit is established from line I.- through contacts 30 to contact 31, through drum segments 31 and 39 to contact 39 through push button contacts 33' and contacts 29 of relay 29 to contact 30. through drum segments 30 and 5I to contact 5|, through the operating winding I6 of switch I6 and byconductor 59 and contacts 30 to line L. Switch I6 thus responds and as hereinbefore set forth in responding'the same provides for operation of the inner slide 2. I During downward movement of the inner slide 2 limit switch 26 closes to establish a maintaining circuit for switch I6 extending from line L through contacts 30 of relay-30 to contact 31, through drum segments 31 and 39 to contact 39, byconductor 6I through limit switch 26 to contact 39, through drum segments 39 and 5I to contact 5I and tablishment of the aforedescribed maintainingcircuit for switch I6 the run push button 33 can be released and switch I6 will remain in closed position until the inner slide 2 approaches its up position. During final movement of the inner slide 2 into its up position limit switch "26 opens to interrupt the maintaining circuit for switch I6 and said switch then drops out to deenergize brake 6 and clutch II for stopping of the inner slide 2 in its up position. During the long inner cycle limit switch 23 acts in the same manner as during the long inner outer cycle to prevent repetition of the former cycle if run push button 33 is maintained depressed.

As hereinbefore set forth, if the innerslide 2 advances too far beyond the outer slide I limit switch 28 is opened to deenergize relay 30 for stopping of both of the slides. Assuming that the slides were stopped in this manner and it is desired to inch outer slide I out of interfering position with the inner slide 2, master switch I1 is moved into its inch outer position and with the same .in this position start button 3| and inch button 33 are depressed. Depression of start an energizing circuit for switch I5 extending from inner slide 2, master switch I! is moved into its "inch inner position and start button 3| and inch button 34 are depressed. Relay 30 is then closed as hereinbefore set forth and the inch button 34 establishes circuit from line L through.

contacts 33 of said relay, through the inch button 34 to contact 38, through drum segments 38 and 5| to contact Iii, through the operating winding l6- oi switch I 6 and through contacts 33 of relay 3' to line L. Switch l6 will thus re- 7 main in closed position as long as push buttons 3| and 34 are maintained depressed, toeffect operation oi inner slide 2.

In connection with the foregoing it should be noted that the invention is not limited to presses having electromagnetically operated brakes and clutches. For example, the invention may be used in connection with presses having electrically controlled pressure operated brakes and clutches. Also it is apparent that the invention is not necessarily limited to a system for effecting the specific cycles of operation hereinbefore described.

What I claim as newand desire to secure by Letters Patent is:

1. In a controller for machine tools having a plurality oi elements provided with separate drives, in combination, a clutch, for controlling each of said drives, and cooperating manual and automatic means for controlling said clutches,

said manual means including a selector switch adapted when set in difl'erent positions to render said automatic means operable to efiect cycling of said elements individually or in a definite sequence and said automatic means comprising a plurality of switches controlled in accordance with the position of said elements.

2. In a controller for machine tools having a plurality of separately driven parts, in combination, a drive for each of said parts including a normally engaged electromagnetically controlled brake and a normally released electromagnetically controlled clutch, and cooperating manual and automatic means for controlling said clutches and brakes to provide selected operations of said parts including individual inching of said parts,- individual cycling thereof or cycling of said parts in a given sequence.

3. The combination with a machine tool having a plurality of reciprocable elements, separate drives for said elements each including '3. normally released electromagnetically controlled clutch and cooperating manual and automatic control means for said clutches including a master switch adapted to be set in diflerent positions to render said automatic means eflective to control said clutches for selected cycles of operation of said elements, said automatic means including a plurality of limit switches controlled in accordance with the position of said elements.

4. The combination with a machine tool having a plurality of reciprocable elements, separate drives for said elements each including a normally released electromagnetically controlled clutch, and cooperating manual and automatic control means for said clutches including a selector switch and a plurality of limit switches for controlling said clutches through the medium of said selector switch, said limit switches providlng for cycling or said elements individually in given settings of said selector switch and for cycling 01' said elements in a given sequence in another setting of said selector switch.

5. The combination with a machine tool having a plurality of reciprocable elements, separate drives for said elements each including a normally released electromagnetically controlled clutch, cooperating manual and automatic control means for said clutches including a selector switch and a plurality of limit switches for controlling said clutches through the medium of said selector switch, said limit switches providing for cycling of said elements individually in given settings of said selector switch and for cycling of said elements in a given sequence in another setting of said selector switch, and means for controlling said clutches in other settings of said selector switch to provide for inching of said elements selectively.

6. The combination with a machine tool having a plurality of slides each movable through a working and a return stroke, and power drives individual to said slides each including a normally released clutch, of an electromagnetic control device for each of said clutches, each of said devices being responsive to eflfect engagement of its associated clutch, and control means for said devices including a selector switch and a plurality of switches controlled in accordance with the position of said slides for controlling said devices through the medium of said selector switch, said devices being controlled by certain of said switches upon setting of said selector switch in a given position to effect operation of said clutches for working and return strokes of said slides in a predetermined sequence, said devices being also controlled individually by certain of said switches upon setting of said selector switch in other positions to render a selected clutch operable to effeet a single working and return stroke of its associated slide without operation of the other of said slides.

7. The combination with a machine tool having a plurality of slides each movable through a working and a return stroke and power drives individual to said slides each including a normally released electromagnetically operated clutch, of control means for said slides including tion of said slides for controlling said clutches through the medium of said selector switch, said clutches being controlled by certain of said switches upon setting of said selector switch in a given position to eifect working and return strokes of said slides in a predetermined sequence, said clutches being also controlled individually by certain of said switches upon setting of said selector switch in other positions to provide for operation of a selected slide through a single working and return stroke without operation of the other of said slides.

8. Th combination with a machine'tool having a plurality of slides each movable through a working and a return stroke, of power drives individual to said slides each including a normally released electromagnetically operated clutch, a manual selector switch, a plurality of switches controlled in accordance with the position of said slides, certain of said switches acting upon setting or said selector switch in a given position to control said clutches for working and return strokes of said slides in a predetermined sequence and certain of said switches also acting upon setting of said selector switch in other given positions to render a selected clutch operable to efliect a single working and return stroke of its associated element without operation of the other of said slides, and manual control means operable upon setting of said selector switch in positions other than those aforementioned to selectively control said clutches for inching operations of said slides.

9. The combination with a machine tool having two separately operable slides each movable through a working and a return stroke, and separate drives for said slides each including a normally released power operated clutch, of an electromagnetic control device associated with each of said clutches for efiecting release and engagement thereof, and means for controlling said devices including a plurality of limit switches controlled in accordance with the position of said slides, said devices being controlled by said switches to effect operation of said clutches for working strokes of said slides in a given sequence and return strokes thereof in a reversed sequence.

ARVID E. LILLQUIST. 

